如何从R中的不同日期数据中找到月平均值？
要从不同日期数据中找到月平均值，我们首先需要从日期列中提取月份和年份，然后使用聚合函数找到平均值。例如，如果我们有一个名为df的数据框，它有三列，分别是x、月和年，那么可以使用以下命令找到月平均值-
aggregate(x~Month+Year,df,mean)
示例1
考虑以下数据框-
Date1<-sample(c(as.Date("2021-01-11"),as.Date("2021-01-15"),as.Date("2021-02-13"),as.Date("2021-02-05"),as.Date("2021-02-09")),20,replace=TRUE)
x<-rnorm(20,25,3.6)
df1<-data.frame(Date1,x)
df1输出结果Date1 x 1 2021-01-11 25.62696 2 2021-02-09 22.36829 3 2021-02-09 20.35938 4 2021-02-09 20.55244 5 2021-02-05 25.81417 6 2021-01-15 24.38129 7 2021-02-09 26.10268 8 2021-01-15 27.67208 9 2021-01-15 30.99175 10 2021-02-09 23.98216 11 2021-02-05 26.80633 12 2021-02-05 29.34845 13 2021-01-15 30.03150 14 2021-02-05 28.04617 15 2021-02-05 21.64901 16 2021-01-15 23.25788 17 2021-02-09 27.60417 18 2021-02-09 18.94671 19 2021-01-11 25.41612 20 2021-02-13 23.14153
使用Date1列在df1中为月和年创建一列-
df1$Month<-months(df1$Date1) df1$Year<-format(df1$Date1,format="%y") df1
Date1 x Month Year 1 2021-01-11 25.62696 January 21 2 2021-02-09 22.36829 February 21 3 2021-02-09 20.35938 February 21 4 2021-02-09 20.55244 February 21 5 2021-02-05 25.81417 February 21 6 2021-01-15 24.38129 January 21 7 2021-02-09 26.10268 February 21 8 2021-01-15 27.67208 January 21 9 2021-01-15 30.99175 January 21 10 2021-02-09 23.98216 February 21 11 2021-02-05 26.80633 February 21 12 2021-02-05 29.34845 February 21 13 2021-01-15 30.03150 January 21 14 2021-02-05 28.04617 February 21 15 2021-02-05 21.64901 February 21 16 2021-01-15 23.25788 January 21 17 2021-02-09 27.60417 February 21 18 2021-02-09 18.94671 February 21 19 2021-01-11 25.41612 January 21 20 2021-02-13 23.14153 February 21
在df1中查找数据的月平均值-
聚合（x~月+年，df1，平均值）
Month Year x 1 February 21 24.20934 2 January 21 26.76823
例2
Date2<-sample(c(as.Date("2020-01-01"),as.Date("2020-04-15"),as.Date("2020-06-03"),as.Date("2020-02-25"),as.Date("2020-10-09")),20,replace=TRUE)
y<-rpois(20,8)
df2<-data.frame(Date2,y)
df2输出结果Date2 y 1 2020-02-25 9 2 2020-01-01 8 3 2020-06-03 12 4 2020-01-01 6 5 2020-01-01 7 6 2020-04-15 9 7 2020-10-09 8 8 2020-10-09 4 9 2020-10-09 7 10 2020-06-03 10 11 2020-06-03 6 12 2020-10-09 10 13 2020-04-15 10 14 2020-10-09 10 15 2020-01-01 11 16 2020-04-15 7 17 2020-10-09 6 18 2020-04-15 7 19 2020-01-01 5 20 2020-10-09 4
使用Date2列在df2中为月和年创建一列-
df2$Month<-months(df2$Date2) df2$Year<-format(df2$Date2,format="%y") df2
Date2 y Month Year 1 2020-02-25 9 February 20 2 2020-01-01 8 January 20 3 2020-06-03 12 June 20 4 2020-01-01 6 January 20 5 2020-01-01 7 January 20 6 2020-04-15 9 April 20 7 2020-10-09 8 October 20 8 2020-10-09 4 October 20 9 2020-10-09 7 October 20 10 2020-06-03 10 June 20 11 2020-06-03 6 June 20 12 2020-10-09 10 October 20 13 2020-04-15 10 April 20 14 2020-10-09 10 October 20 15 2020-01-01 11 January 20 16 2020-04-15 7 April 20 17 2020-10-09 6 October 20 18 2020-04-15 7 April 20 19 2020-01-01 5 January 20 20 2020-10-09 4 October 20
在df2中查找数据的月平均值-
聚合（y~月+年，df2，平均值）
Month Year y 1 April 20 8.250000 2 February 20 9.000000 3 January 20 7.400000 4 June 20 9.333333 5 October 20 7.000000